1. Field of the Invention
The invention relates to apparatus for mixing at least one additional gas into a main flow of a gas flowing in a cylindrical conduit.
2. Description of the Prior Art
Mixing apparatus for gases, apart from burners, can be subdivided into two types, i.e. flow mixers and rotating mixers; the invention is concerned with flow mixers and more specifically with centrifugal mixers, in which whereby one or more lines for the gas to be admixed debouch tangentially into the cylindrical main conduit. Existing gas mixers have the disadvantage, however, that the mixing must take place over an excessively long section of the main conduit, because of the requirements of controlling noise (a shorter mixing path can be achieved by increasing the prepressure of the injected gas to above-critical value, which results in supersonic inflow velocities and the noise associated therewith).
In particular if two gaseous fuels of different combustion values are to be mixed, before being burnt in a burner, the mixing should be completed over a short distance (10 D where D is the conduit diameter), since otherwise the burner will burn irregularly and even pulsatingly. Also if control of the calorific-value of the fuel gas is attempted, long travel times from the mixer to the burner, must be avoided, in view of the instability of the control and therefore aforesaid burner problems.